Brush device

ABSTRACT

A brush device having a brush holding frame made of an insulation material provided with a plurality of brush accommodating portions which are open at end portions thereof in the axial direction and at inner peripheral portions thereof in the radial direction, and a pair of protruded portions at opposing outer ends thereof in the radial direction; brushes accommodated in the brush accommodating portions along with brush springs, press-contacting a commutator of a direct current machine; an insulation plate touching an end face of the brush holding frame in the axial direction, covering the open portions at the end portions of the brush accommodating portion; and a pair of attaching pieces mounted on and pinching both end faces of the pair of protruded portions of the brush holding frame thereby fixing the insulation plate to the end face of the brush holding frame in the axial direction comprises a pair of stopper protrusion portions protruded in the axial direction provided at intermediate positions situated between the pair of protruded portions in the peripheral direction on the end face of the brush holding frame; and a pair of engaging holes in the insulation plate for pressing in and fixing the pair of stopper protrusions, provided in correspondence therewith.

The present invention relates to a brush device for a direct currentmachine such as a starter motor.

FIGS. 4A and 4B show a front view and a side view of a firstconventional brush device. In FIGS. 4A and 4B, a reference numeral 1designates a commutator of a direct current machine, 4, a brush holdingframe, for instance, formed by a synthetic resin, which is provided withpairs of brush accommodating portions 4a and 4b which are open at endportions thereof and at inner peripheral portions thereof in the radialdirection. The brush accommodating portions 4a accommodate positivebrushes 5a and brush springs 8, and the brush accommodating portions 4baccommodate negative brushes 5b and the brush springs 8. In the brushholding frame 4, a pair of protruded portions 4c are extended in theradial direction, on the side of an end face of which a stepped stopperportion 4d is formed, and a pair of stopper protrusions 4e are formed atintermediate positions with respect to the peripheral direction of thepair of protruded portions 4c. As shown by a chain line in FIG. 4A, aninsulation plate 12 touches an end face of the brush holding frame 4,engages with the stepped stopper portion 4d and the stopper protrusions4e, thereby positioning the insulation plate 12 vertically andhorizontally, and covers the open portions of the end portions of thebrush accommodating portions 4a and 4b. FIG. 6 is a front view of theinsulation plate 12. FIGS. 5A and 5B are sectional diagrams of the brushaccommodating portion 4a and the stopper protrusion 4e of FIG. 4A.

In FIGS. 4A and 4B, the insulation plate 12 is pinched and fixed to theprotruded portions 4c by a pair of attaching pieces 9a and 9b made of ametallic material. Lead wires 6a are extended from the pair of brushes5a and are connected to a lead wire 7. The lead wire 7 is fitted with agrommet 11 and connected to a terminal 10 at an end thereof. Lead wires6b are extended from the pair of brushes 5b and connected to theattaching piece 9b.

As shown in FIG. 4B, the brush device integrated as above is mounted onan inner face of an end portion of a rear bracket 2 (shown by a chainline) of a starter motor by screwing screws 3 into tapped holes 9cthereby fixing the attaching pieces 9a and 9b. The rear bracket 2 fixedwith the brush device is connected to a front bracket (not shown) bythrough bolts through a yoke (not shown) of the starter motor. Thebrushes 5a and 5b are press-contacted to the commutator (shown by achain line) for flowing current.

In the above conventional brush device, the insulation plate 12 isstopped of its relative motion vertically and horizontally by thestepped stopper portion 4d of the brush holding frame 4 and the stopperprotrusions 4e, and is pinched by the attaching pieces 9a and 9b.However, there is a play in the assembly due to working tolerances ofthe respective corresponding parts. Especially, although the insulatingplate 12 is pinched by the attaching pieces 9a and 9b only at the twoplaces on the top side and on the bottom side thereof, the left andright portions thereof float from the end portions of the brush holdingframe 4 and vibrate by an outside vibration. As a result, in theinsulating plate 12, wear is promoted at the engaging portions by thisvibration, the play is magnified, a mismatch is caused and a trouble isbrought about in the receiving operation of the brushes 5a and 5b atsides thereof in the width direction.

FIGS. 12A and 12B show a front view and a side view of a secondconventional brush device. In FIGS. 12A and 12B, a reference numeral 101designates a commutator of a direct current machine, 104, a brushholding frame, for instance, formed by a synthetic resin, which isprovided with pairs of brush accommodating portions 104a and 104b whichare open at end portions thereof and at inner peripheral portionsthereof in the radial direction. The brush accommodating portions 104aaccommodate positive brushes 105a and brush springs 108, whereas thebrush accommodating portions 104b accommodate negative brushes 105b andthe brush springs 108. In the brush holding frame 104, a pair ofprotruded portions 104c are extended in the radial direction. As shownin FIG. 12A by a chain line, an insulation plate 112 touches an end faceof the brush holding frame 104, engages with a stepped stopper portion104d and covers the open portions at the end portions of the brushaccommodating portions 104a and 104b. FIG. 13 is a sectional diagramshowing the brush accommodating portion 104a of FIG. 12A.

In FIGS. 12A and 12B, the insulation plate 112 are pinched and fixed tothe protruded portions 104c by a pair of attaching pieces 109a and 109bmade of a metallic material. Lead wires 106a are extended from the pairof brushes 105a and connected to a lead wire 107. The lead wire 107 isfitted with a grommet 111 and is connected to a terminal 110 at an endthereof. Furthermore, lead wires 106b are extended from the pair ofbrushes 105b and connected to the attaching pieces 109b. FIG. 14 is asectional diagram taken along a line A₈ --A₈ of FIG. 12A. A numeral 104fdesignates a screw accommodating hole of an attaching screw 103 (referto FIG. 12B) provided at the protruded portion 104c of the brush holdingframe 104. A numeral 104i designates slots provided at the protrudedportions 104c for passing burring portions which are provided withtapped holes 109c of the attaching pieces 109a and 109b.

As shown in FIG. 12B, the brush device integrated as above, is fixed toan inner face of an end portion of a rear bracket 102 (shown by a chainline) of a starter motor, by screwing the screws 103 into the tappedholes 109c thereby fixing the attaching pieces 109a and 109b. The rearbracket 102 fixed with the brush device is connected to a front bracket(not shown) by through bolts through a yoke (not shown) of the startermotor. The brushes 105a and 105b are press-contacted to the commutator101 (shown by a chain line) for flowing current.

In the above conventional brush device, the attaching pieces 109a and109b are only fixed by pinching them to the protruded portions 104c ofthe brush holding frame 104. Therefore, when the direct current machinereceives a vibration, the brush holding frame 104 and the attachingpieces 109a and 109b vibrate separately, wear is generated at thefitting portions for the both, a play is generated therebetween,destruction is caused and the contact operation of the brushes 105a and105b to the commutator 1 is hampered. Furthermore, the positioningaccuracy of the attaching pieces 109a and 109b with respect to theprotruded portions 104c of the brush holding frame 104, is low and theoperation of attaching the brush device to the rear bracket isdifficult.

FIGS. 18A and 18B are a front view and a side view of a thirdconventional brush device. In FIGS. 18A and 18B, a reference numeral 201designates a commutator of a direct current machine, and 204, a brushholding frame, for instance, formed of a synthetic resin, which isprovided with pairs of brush accommodating portions 204a and 204b whichare open at end portions thereof and at inner peripheral portionsthereof in the radial direction. The brush accommodating portions 204aaccommodate positive brushes 205a and brush springs 208, whereas thebrush accommodating portions 204b accommodate negative brushes 205b andthe brush springs 208. In the brush holding frame 204, a pair ofprotruded portions 204c are extended in the radial direction. As shownin FIG. 18A by a chain line, an insulation plate 212 touches an end faceof the brush holding frame 204, engages with a stepped stopper portion204d and covers the open portions at the end portions of the brushaccommodating portions 204a and 204b. FIG. 19 is a sectional diagram ofthe brush accommodating portion 204a of FIG. 18A. In FIGS. 18A and 18B,the insulation plate 212 is pinched and fixed to the protruded portions204c by a pair of attaching pieces 209a and 209b made of a metallicmaterial. Lead wires 206a are extended from the pair of brushes 205a andare connected to a lead wire 207. The lead wire 207 is fitted with agrommet 211, and is connected to a terminal 210 at an end thereof. Leadwires 206b are extended from the pair of brushes 205b and are connectedto the attaching piece 209b.

As shown in FIG. 18B, the brush device integrated as above, is mountedon an inner face of an end portion of a rear bracket 202 (shown by achain line) of a starter motor, by screwing screws 203 into tapped holes209c thereby fixing the attaching pieces 209a and 209b. The rear bracket202 attached with the brush device is connected to a front bracket (notshown) by through bolts through a yoke (not shown) of the starter motor.The brushes 205a and 205b are press-contacted to the commutator 201(shown by a chain line) for flowing current.

In the U-shaped attaching pieces 209a and 209b of the conventional brushdevice, as shown in FIG. 20A by a side sectional diagram and FIG. 20B bya bottom view, when a tapping is performed to form the tapped holes 209cat first straight portions thereof, since a space between the firststraight portion and a second straight portion thereof is small, a frontend of a tap 215 touches the second straight portion, and therefore, acomplete tapping can not be performed. Therefore, several kinds ofspecial taps are to be prepared and exchanged to successively work out acomplete screw out of the incomplete screw and the machining thereof isdifficult. Furthermore, when the length of a female screw is shortenedto avoid the above problem, the number of the thread ridges screwed inthe tapped holes becomes small and the thread ridges are crushed by thescrewing.

FIGS. 24A and 24B show a front view and a side view of a fourthconventional brush device. In FIGS. 24A and 24B, a reference numeral 301designates a commutator of a direct current machine, and 304, a brushholding frame, for instance, formed by a synthetic resin, which isprovided with pairs of brush accommodating portions 304a and 304b andwhich are open at end portions thereof and at inner peripheral portionsthereof in the radial direction. The brush accommodating portions 304aaccommodate positive brushes 305a and brush springs 308, whereas thebrush accommodating portions 304b accommodate negative brushes 305b andthe brush springs 308. In the brush holding frame 304, a pair ofprotruded portions 304c are extended in the radial direction. As shownin FIG. 24A by a chain line, an insulation plate 312 touches an end faceof the brush holding frame 304, engages with a stepped stopper portion304d and covers the open portions of the end portions of the brushaccommodating portions 304a and 304b. FIG. 25 is a sectional diagramshowing the brush accommodating portion 304a of FIG. 24A.

In FIGS. 24A and 24B, the insulation plate 312 is pinched and mounted tothe protruded portions 304c by a pair of attaching pieces 309a and 309b.Lead wires 306a are extended from the pair of brushes 305a and areconnected to a lead wire 307. The lead wire 307 is fitted with a grommet311 and is connected to a terminal 310 at an end thereof. Lead wires306b are extended from the pair of brushes 305b and are connected to theattaching piece 309b.

The integration of the brush device assembled as above to a motor iscarried out as follows. First, a front bracket of the starter motor isplaced in a standing setup of a motor, on which a yoke portion isplaced. The armature is inserted into the assembly of the front of theyoke portion with the commutator 301 placed on the top side thereof. Thebrush device is tentatively placed at the periphery of the commutator301. A rear bracket 302 is placed on the yoke from the top side. Throughbolts 316 are passed through thereby tightening and connecting the rearbracket 302 to the front bracket. Next, screws 303 are screwed to tappedholes 309c of the attaching pieces 309a and 309b from the top side ofthe rear bracket 302, thereby fixing the brush device andpress-contacting the brushes 305a and 305b to the commutator 301.

In the above conventional brush device, as for the mounting thereof, thepositioning of the attaching pieces 309a and 309b of the brush device inthe peripheral direction with respect to the positions of the screws 303of the rear bracket 302, is difficult and takes much time.

It is an object of the present invention to solve the above problem ofthe first conventional example and to provide a brush device wherein aninsulation plate is fixed to an end face of a brush holding framewithout play, wear at engaging portions is eliminated and a receivingoperation at one side in the width direction of a brush is firmlymaintained.

It is an object of the present invention to solve the problem of thesecond conventional example and to provide a brush device whereinattaching pieces are fixed to protruded portions of a brush holdingframe with high positioning accuracy, a play between both is avoided,wear or destruction owing thereto at both engaging portions iseliminated and an operation of attaching thereof to a rear bracket isfacilitated.

It is an object of the present invention to solve the problem of thethird conventional example and to provide a brush device wherein atapped hole working of a required length of a U-shaped attaching piece,can easily be carried out.

It is an object of the present invention to solve the problem of thefourth conventional example and to provide a brush device wherein anattaching piece of the brush device can easily be positioned to anattaching screw from a rear bracket thereby promoting the operationalperformance of integration.

According to a first aspect of the present invention, there is provideda brush device having a brush holding frame made of an insulationmaterial provided with a plurality of brush accommodating portions whichare open at end portions thereof in the axial direction and at innerperipheral portions thereof in the radial direction, and a pair ofprotruded portions at opposing outer ends thereof in the radialdirection; brushes accommodated in said brush accommodating portionsalong with brush springs, press-contacting a commutator of a directcurrent machine; an insulation plate touching an end face of said brushholding frame in the axial direction, covering the open portions at saidend portions of the brush accommodating portion; and a pair of attachingpieces mounted on and pinching both end faces of said pair of protrudedportions of the brush holding frame thereby fixing said insulation plateto said end face of the brush holding frame in the axial directioncomprising:

a pair of stopper protrusion portions protruded in the axial directionprovided at intermediate positions situated between said pair ofprotruded portions in the peripheral direction on the end face of thebrush holding frame; and

a pair of engaging holes in the insulation plate for pressing in andfixing said pair of stopper protrusions, provided in correspondencetherewith.

According to a second aspect of the present invention, there is providedthe brush device according to the first aspect, further comprisingcut-off portions provided at the inner peripheral portions of the pairof engaging holes and cut off in the radial direction thereof.

According to a third aspect of the present invention, there is provideda brush device having a brush holding frame made of an insulationmaterial provided with a plurality of brush accommodating portions whichare open at end portions thereof in the axial direction and at innerperipheral portions thereof in the radial direction, and a pair ofprotruded portions at opposing outer ends thereof in the radialdirection; brushes accommodated in said brush accommodating portionsalong with brush springs, press-contacting a commutator of a directcurrent machine; an insulation plate touching an end face of said brushholding frame in the axial direction, covering the open portions at saidend portions of the brush accommodating portion; a pair of U-shapedattaching pieces mounted on and pinching both end faces of said pair ofprotruded portions of the brush holding frame thereby fixing saidinsulation plate to said end face of the brush holding frame, and fixedto an inner end portion of a rear bracket of said direct current machinecomprising:

engaging protrusions provided on inner faces of first straight portionsof said U-shaped attaching pieces opposing second straight portionsthereof having tapped holes; and

engaging holes provided at rear end portions of the protruded portionsof the brush holding piece for engaging with said engaging protrusionsof the U-shaped attaching pieces.

According to a fourth aspect of the present invention, there is providedthe brush device according to the third aspect, further comprisingstepped portions provided at the rear end portions of the protrudedportions of the brush holding piece for contacting similarly steppedportions provided at end portions of the first straight portions of theU-shaped attaching pieces.

According to a fifth aspect of the present invention, there is provideda brush device having a brush holding frame made of an insulationmaterial provided with a plurality of brush accommodating portions whichare open at end portions thereof in the axial direction and at innerperipheral portions thereof in the radial direction, and a pair ofprotruded portions at opposing outer ends thereof in the radialdirection; brushes accommodated in said brush accommodating portionsalong with brush springs, press-contacting a commutator of a directcurrent machine; an insulation plate touching an end face of said brushholding frame in the axial direction, covering the open portions at saidend portions of the brush accommodating portion; and a pair of U-shapedattaching pieces mounted on and pinching both end faces of said pair ofprotruded portions of the brush holding frame thereby fixing saidinsulation plate to said end face of the brush holding frame in theaxial direction comprising:

tap accommodating holes previously provided for accommodating front endsof taps for machining tapped holes at positions of first straightportions of said U-shaped attaching pieces in correspondence to tappedholes of second straight portions thereof.

According to a sixth aspect of the present invention, there is provideda brush device having a plurality of and a brush holding frame formed bya synthetic provided with a plurality of brush accomodating portionsresin comprising:

a pair of guiding-through portions provided at outer peripheral sides ofsaid brush holding frame in the axial direction;

a pair of through bolts passing through said pair of guiding-throughportions from a rear bracket of a direct current machine; and

attaching pieces for fixing said brush holding frame to said rearbracket, positioned by passing said pair of through bolts through thepair of guiding-through portions via the brush holding frame, saidattaching pieces being screwed to the rear bracket by attaching screws.

In the first and second aspects of this invention, the insulation plateis positioned and fixed to the end face of the brush holding frame bypressing the pair of engaging holes to the corresponding pair ofprotruded stopper portions, without generating a play, covering the endportions of the brush accommodating portions in the axial direction.Furthermore, by providing the cut-off portions at the inner peripheriesof the engaging holes, the engaging holes can easily be pressed to theprotruded engaging portions even when there is a positional deviationbetween the engaging holes and the protruded engaging portions byworking tolerances.

In the third and fourth aspects of the present invention, as for theattaching pieces fitted to and mounted on the protruded portions of thebrush holding frame, the engaging protrusions engage with the engagingholes of the protruded portions of the brush holding frame, therebyeliminating the play between the both and promoting the positioningaccuracy.

Furthermore, since the end portion of the first straight portion pieceof the attaching piece contact the stepped portion of the protrudedportion, the play between the both is further reduced.

In the fifth aspect of the present invention, in working out the tappedhole by the tap at the first straight portion of the attaching piece,the front end portion of the tap is accommodated by the tapaccommodating portion of the second piece thereof, thereby working acomplete tapped hole in a single motion by a single kind of tap.

In the sixth aspect of the present invention, in the assemblingoperation, when the through bolts are to be passed in the axialdirection from the rear bracket through the brush device which istentatively placed on the commutator of the armature in the standingsetup, the brush holding frame is positioned by passing the throughbolts through the guiding-through portions of the brush holding frame.In this way, the tapped holes of the attaching pieces are positioned inaccordance with the positions of the attaching male screw from the rearbracket. Therefore, the brush device can easily be attached to the motorby the attaching male screws.

In the drawings:

FIG. 1A and 1B are respectively a front diagram and a side diagram ofthe first embodiment of a brush device according to the presentinvention;

FIGS. 2A and 2B are sectional diagrams taken along a line A₂ --A₂ and aline B₂ --B₂ of FIG. 1A, respectively;

FIG. 3A is a front view of an insulation plate of FIG. 1A and FIG. 3B, amagnified diagram of an engaging hole portion of FIG. 3A;

FIGS. 4A and 4B are respectively a front diagram and a side diagram of afirst conventional brush device;

FIGS. 5A and 5B are sectional diagrams taken along line A₅ --A₅ and a B₅--B₅ of FIG. 4A;

FIG. 6 is a front diagram of an insulation plate of FIG. 4A;

FIGS. 7A and 7B are respectively a front diagram and a side diagram of asecond embodiment of a brush device according to the present invention;

FIG. 8 is a sectional diagram taken along a line A₂ --A₂ of FIG. 7A;

FIG. 9A is a sectional diagram taken along a line A₃ --A₃ of FIG. 7A andFIG. 9B, a bottom view of a protruded portion of FIG. 9A;

FIG. 10 is a bottom view of a protruded portion of a brush holding frameshowing a third embodiment of this invention and corresponding to FIG.9B;

FIGS. 11A, 11B and 11C are respectively side views of attaching piecesshowing a fourth, a fifth and a sixth embodiments of this invention;

FIGS. 12A and 12B are respectively a front view and a side view of asecond conventional brush device;

FIG. 13 is a sectional diagram taken along a line A₇ --A₇ of FIG. 12A;

FIG. 14 is a sectional diagram taken along a line A₈ --A₈ of FIG. 12A;

FIGS. 15A and 15B are respectively a front view and a side view of aseventh embodiment of a brush device according to the present invention;

FIG. 16 is a sectional diagram taken along a line A₂ --A₂ of FIG. 15A;

FIG. 17A is a side sectional diagram showing a working of a tapped holeof an attaching piece of FIGS. 15A and 15B and FIG. 17B, a bottom viewof the attaching piece of FIG. 17A;

FIGS. 18A and 18B are respectively a front view and a side view of athird conventional brush device;

FIG. 19 is a sectional diagram taken along a line A₅ --A₅ of FIG. 18A;

FIG. 20A is a side sectional diagram showing a working of a tapped holeof an attaching piece of FIGS. 18A and 18B, and FIG. 20B, a bottom viewof the attaching piece of FIG. 20A;

FIGS. 21A and 21B are respectively a front diagram and a side diagram ofan eighth embodiment of a brush device according to the presentinvention;

FIG. 22 is a sectional diagram taken along a line A₂ --A₂ of FIG. 21A;

FIG. 23 is a perspective diagram showing a ninth embodiment of aguiding-through portion of a brush holding frame of this invention;

FIGS. 24A and 24B are respectively a front diagram and a side diagram ofa fourth conventional brush device; and

FIG. 25 is a sectional diagram taken along a line A₅ --A₅ of FIG. 24A.

EXAMPLE 1

FIGS. 1A and lB are respectively a front diagram and a side diagram of abrush device of this invention, wherein notations 1 through 3, 5a, 5b,6a, 6b, 7, 8, 9a through 9c, 10 and 11 are the same as those in FIGS. 4Aand 4B. A reference numeral 20 designates a brush holding frame, forinstance, formed by a synthetic resin, which is provided with pairs ofbrush accommodating portions 20a and 20b which are open at end portionsthereof in the axial direction and at the inner peripheral portionsthereof in the radial direction. The brush accommodating portions 20aaccommodate the positive brushes 5a and the brush springs 8, whereas thebrush accommodating portions 20b accommodate the negative brushes 5b andthe brush springs 8. In the brush holding frame 20, a pair of protrudedportions 20c provided on the top side and the bottom side thereof in theradial direction, are extended and a stepped stopper portion 20d isformed on the side of an end face thereof. Furthermore, a pair ofprotruded stopper portions 20e are provided on the end face of the brushholding frame 20 at intermediate positions with respect to theperipheral direction of the pair of protruded portions 20c.

As shown in FIGS. 1A and lB, an insulation plate 21 touches the end faceof the brush holding frame 20 in the axial direction, engages with thestepped stopper portion 20d and engaging holes 21a provided on the leftside and the right side of the insulation plate 21, are pressed in theprotruded stopper portions 20e, thereby fixing and positioning theinsulation plate 21. The insulation plate 21 is pinched and retained tothe protruded portions 20c by the U-shaped attaching pieces 9a and 9b.FIG. 2A is a sectional diagram showing the brush accommodating portions20a. FIGS. 2B is a sectional diagram showing the protruded stopperportion 20e. At the front end of the protruded stopper portion 20e, achamfered portion 20f is provided such that an engaging hole 21a of theinsulation plates 21 is easily fitted thereto. The chamfered portion 20fmay be of an arcuate face.

FIG. 3A is a front view showing the insulation plate 21. FIG. 3B is amagnified diagram showing the engaging hole 21a of the insulation plate21. The engaging hole 21a is provided with an inner diameter smallerthan an outer diameter of the protruded stopper portion 20e by aninterference A pair of cut-off portions 21b are provided at the innerperipheral portion of the engaging hole 21a in the radial direction. Acircular portion is provided at the inner end of the cut-off portion 21bhaving a diameter larger than a cut-off width of the straight portionthereof. Furthermore, the circular portion may be substituted by aportion having an arcuate form.

The insulation plate 21 of which engaging holes 21a are pressed in theprotruded stopper portions 20e of the brush holding frame 20, engageswith the stepped stopper portion 20d of the brush holding frame 20 andtouches the end face of the brush holding frame 20. In this state, theattaching pieces 9a and 9b are fitted to the protruded portions 20cthereby pinching and fixing the insulation plate 21. By providing thecut-off portions 21b to the engaging holes 21a of the insulation plate21 at their inner peripheries, the protruded stopper portions 20e caneasily be pressed in and fixed to the engaging hole 21a by the elasticdeformation of the inner peripheries, even when the positions of theengaging holes 21a are a little deviated from those of the correspondingprotruded stopper portions 20e.

As stated above, according to the present invention, a pair of protrudedstopper portions are provided protruded in the axial direction, atintermediate positions between the pair of protruded portions of thebrush holding frame in the peripheral direction and a pair of engagingholes are provided in the insulation plate which are pressed in theprotruded stopper portions correspondingly. Therefore, the insulationplate is fixed to the end face of the brush holding frame with nofloating separation, whereby vibration or generation of play isprevented and the receiving action of the brushes at side faces thereofin the width direction, is maintained with certainty. Furthermore, byproviding the cut-off portions at the inner peripheries of the engagingholes of the insulation plate, the protruded stopper portions can easilybe pressed in and fixed to the engaging holes even when there is alittle positional deviation between the engaging holes and the protrudedstopper portions of the brush holding frame.

EXAMPLE 2

FIGS. 7A and 7B are respectively a front diagram and a side diagram of asecond embodiment of a brush device according to the present invention,wherein notations 101 to 103, 105a, 105b, 106a, 106b, 107, 108, 110 and111 are the same as in FIG. 12. A reference numeral 120 designates abrush holding frame, for instance, formed by a synthetic resin which isprovided with pairs of brush accommodating portions 120a and 120b whichare open at end portions thereof in the axial direction and innerperipheral portions thereof in the radial direction. The brushaccommodating portions 120a accommodate the positive brushes 105a andthe brush springs 108, whereas the brush accommodating portions 120baccommodate the negative brushes 105b and the brush springs 108. In thebrush holding frame 120, a pair of protruded portions 120c are extendedto the top side and the bottom side thereof in the radial direction, onthe side of an end face of which a stepped stopper portion 120d isformed.

As shown in FIGS. 7A and 7B, an insulation plate 121 touches the endface of the brush holding frame 120 in the axial direction, and engageswith the stepped stopper portion 120d. The insulation plate 121 ispinched and retained to the protruded portions 120c by U-shapedattaching pieces 122a and 122b made of a metallic material. Tapped holes122c are provided at straight portions of the attaching pieces 122a and122b. FIG. 8 is a sectional diagram showing the brush accommodatingportion 120a.

FIG. 9A is a sectional diagram taken along a line A₃ --A₃ of FIG. 7A.FIG. 9B is a bottom view of the protruded portion 120c of FIG. 9A. Anengaging protrusion 122d is provided at an inner face of the otherstraight portion of the attaching piece 122b by pressing, which engageswith an engaging hole 120f (also utilized as a screw accommodating holefor the screw 103) provided at the protruded portion 120c of the brushholding frame 120, performing a positioning and removing a play. Astepped portion 120g is provided at the other end face of the protrudedportion 120c, or the rear side thereof, contacting an edge portion ofthe other straight portions of the attaching piece 122b. In this way,the play between the attaching piece 122b and the brush holding frame120 is further reduced. A chamfered portion 120h is provided at an edgeportion of a rear face on the outer periphery of the protruded portion120c, thereby facilitating the fitting of the attaching pieces 122a and122b. Slots 120i are provided at edge faces of the protruded portions120c for passing burring portions provided with tapped holes 122c of theattaching pieces 122a and 122b. Furthermore, similar to the attachingpiece 122b, the attaching piece 122a is also provided with the engagingprotrusion 122d at an inner face of the other straight portion thereof,which engages with the engaging hole 120f of the protruded portion 120c,and an edge portion of the other straight portion thereof contacts thestepped portion 120g.

When the attaching pieces 122a and 122b are fitted to and pinch theprotruded portions 120c of the brush holding frame 120, the engagingprotrusions 122d engage with the engaging holes 120f, almost eliminatingthe play and promoting the positional accuracy. Furthermore, since nocurrent flows in the attaching piece 122a, the attaching piece 122a maybe made of a resilient material. However, since current flows in theattaching piece 122b to the ground, the attaching piece 122b ispreferably made of an electricity-conductive metallic material, such asa brass or a phosphor bronze.

EXAMPLE 3

FIG. 10 is a bottom view showing a third embodiment of this inventionand corresponding to the protruded portion 120c of the brush holdingframed 120 of FIG. 9B. A cut-off portion 120j is provided at anintermediate portion of the stepped portion 120g of the protrudedportion 120c. The edge portions of the other straight portions of theattaching pieces 122a and 122b are formed to contact the steppedportions 120g and the cut-off portions 120j, thereby engaging therewithalso in the width direction and further preventing the play.

EXAMPLES 4 TO 6

FIGS. 11A, 11B and 11C are side diagrams of the attaching pieces 122aand 122b showing a fourth to a sixth embodiments, wherein the engagingprotrusions 122d are formed by pressing such that the engagingprotrusions 122d are easily inserted into the engaging holes 120f of theprotruded portions 120c of the brush holding frame 120. In FIG. 11A, anend face of the engaging protrusion 122d is formed into a tapered face.In FIG. 11B, an end face of a cylinder of the engaging protrusion 122dis formed into a spherical shape. In FIG. 11c, an end face of theengaging protrusion 122d is made spherical.

Furthermore, in the above respective Examples, only one engagingprotrusion 122d is provided at each of the attaching pieces 122a and122b. However, a plurality of engaging protrusions 122d may be providedto a single attaching piece in the width direction and a plurality ofengaging holes may be provided at the protruded portion 122c of thebrush holding frame 120 which correspondingly engage therewith.

As state above, according to the present invention, the engagingprotrusions are provided at the inner faces of the other straightportions of the U-shaped attaching pieces and the engaging holes areprovided at the protruded portions of the brush holding frame whichengage with the engaging protrusions. Therefore, the attaching piecespinch and are fixed to the protruded portions without play, therebyeliminating wear at the fitting portions and the destruction owingthereto, promoting the positioning accuracy and facilitating themounting operation thereof to a rear bracket.

EXAMPLE 7

FIGS. 15A and 15B are respectively a front diagram and a side diagramshowing a seventh embodiment of a brush device according to the presentinvention, wherein notations 201 through 203, 205a, 205b, 206a, 206b,207, 208, 210 and 211 are the same as in FIGS. 18A and 18B. A referencenumeral 220 is a brush holding frame, for instance, formed of asynthetic resin, provided with pairs of brush accommodating portions220a and 220b, which are open at end portions thereof in the axialdirection and at inner peripheral portions thereof in the radialdirection. The accommodating portions 220a accommodate the positivebrushes 205a and the brush springs 208, whereas the accommodatingportions 220b accommodate the negative brushes 205b and the brushsprings 208. In the brush holding frame 220, a pair of protrudedportions 220c are extended to the top side and the bottom side thereof,on the side of an end face of which a stepped stopper portion 220d isformed.

As shown in FIGS. 15A and 15B, an insulation plate 221 touches the endface of the brush holding frame 220 in the axial direction, and engageswith the stepped stopper portion 220d. The insulation plate 221 ispinched and retained to the protruded portions 220c by U-shapedattaching pieces 222a and 222b made of a metallic material. FIG. 16 is asectional diagram showing the brush accommodating portion 220a.

As shown in FIGS. 17A and 17B, a side sectional diagram and a bottomview respectively, in the attaching pieces 222a and 222b, in contrast tofirst straight portions of the U-shaped attaching pieces wherein tappedholes 222c are formed, tap accommodating holes 222d having holediameters which are equal to or larger than the diameter of the tappedholes 222c, are previously provided in second straight portions of theU-shaped attaching pieces at positions corresponding to those of thetapped holes 222c. This tap accommodating hole 222d may be formed bycutting off the attaching piece in a U-shaped form as shown in FIG. 17Bor in a circular form. In forming the tapped hole 222c at the firststraight portion by a tap 215, the front end portion of the tap 215 isaccommodated by the tap accommodating hole 222d, thereby easily forminga complete female screw by a single kind of tap.

As stated above, according to the present invention, the tapaccommodating holes which accommodate the front end portion of the tap,are previously provided in the second straight portions of the U-shapedattaching pieces at the positions corresponding to the tapped holesformed at the first straight portions of the U-shaped attaching pieces.Therefore, in forming the tapped holes in the first straight portions,the complete female screws having a required length can easily be formedby a single kind of tap, and the fixing thereof by attaching screws froma rear bracket can be performed with certainty.

EXAMPLE 8

FIGS. 21A and 2lB are respectively a front diagram and a side diagram ofan eighth embodiment of a brush device according to the presentinvention, wherein notations 301 through 303, 305a, 305b, 306a, 306b,307, 308, 309a, 309b, 309c, 310 and 311 are the same as in FIGS. 24A and24B. A reference numeral 320 designates a brush holding frame, forinstance, formed by a synthetic resin, provided with pairs of brushaccommodating portions 320a and 320b, which are open at end portionsthereof in the axial direction and at inner peripheral portions thereofin the radial direction. The brush accommodating portions 320aaccommodate the positive brushes 305a and the brush springs 308, whereasthe brush accommodating portions 320b accommodate the negative brushes305b and the brush springs 308. In the brush holding frame 320, a pairof protruded portions 320c are extended to the top side and bottom sidethereof in the radial direction, on the side of an end face of which astepped stopper portion 320d is formed.

As shown in FIGS. 21A and 21B, an insulation plate 321 touches the endface of the brush holding frame 320 in the axial direction, and engageswith the stepped stopper portion 320d. FIG. 22 is a sectional diagramshowing the brush accommodating portion 320a. In FIGS. 21A and 21B, anotation 320m designates guiding-through portions provided at the brushholding frame 320, composed of guide holes which are positioned andguided by passing through bolts 316 (shown by a chain line) therethroughin the axial direction. At the entrance of the guiding-through portion320m, a tapered face 320n is formed, thereby easily passing a front endof the through bolt 316 and performing the positioning.

The mounting of the brush device integrated as above to the motor, isperformed as in the conventional device. The through bolt 316 insertedfrom the rear bracket on the top side, is guided by the tapered face320n at the entrance of the guiding-through portion 320m and the brushholding frame 320 is positioned by passing the through bolts 316 throughthe guiding-through portions 320m. In this way, the tapped holes 309c ofthe attaching pieces 309a and 309b are aligned to the screws 303 of therear bracket 302, thereby easily performing the attaching the attachingpieces to the rear bracket.

EXAMPLE 9

FIG. 23 is a perspective view of a guiding-through portion of a brushholding frame showing a ninth embodiment of this invention. At theperiphery of the brush holding frame 320, a pair of guiding-throughportions 320p are formed on the both sides thereof at positions throughwhich the through bolts 316 pass. The guiding-through portion 320p isconstructed as follows. A notation 320r designates a pair of opposingguiding protrusions, between which a guiding slot 320s is formed whichpasses and guides the through bolt 316 in the axial direction. At theentrance of the guiding slot 320s, tapered faces 320t are formed,thereby facilitating the insertion of the through bolt 316.

As stated above, according to the present invention, a pair ofguiding-through portions are provided at the outer periphery of thebrush holding frame on the both sides thereof which guides and positionsthe through bolts from the rear bracket in the axial direction.Therefore, the tapped holes of the attaching pieces pinching and fixingthe brush holding frame, are aligned with the position of the screwsfrom the rear bracket, and the attaching is easily performed, therebyfacilitating the mounting operation. Accordingly, an automation ofmounting is made possible.

We claim:
 1. A brush device comprising:a brush holding frame made of aninsulation material provided with a plurality of brush accommodatingportions, said brush accommodating portions being open at end portionsin an axial direction and at inner peripheral portions in a radialdirection, and a pair of protruded portions at opposing outer ends ofsaid brush holding frame in the radial direction; brushes accommodatedin said brush accommodating portions along with brush springs,press-contacting a commutator of a direct current machine; an insulationplate touching an end face of said brush holding frame in the axialdirection, covering the open portions at said end portions of the brushaccommodating portion; a pair of attaching pieces mounted on andpinching both end faces of each pair of protruded portions of the brushholding frame thereby fixing said insulation plate to said end face ofthe brush holding frame in the axial direction; a pair of stopperprotrusion portions protruded in the axial direction provided atintermediate positions situated between said pair of protruded portions,equidistant from said protruded portions, in the peripheral direction onthe end face of the brush holding frame; and a pair of engaging holes inthe insulation plate, provided in correspondence with said stopperprotrusions, for pressing in and fixing said pair of stopperprotrusions, to thereby reduce vibration.
 2. The brush device accordingto claim 1, further comprising cut-off portions provided at innerperipheral portions of the pair of engaging holes and cut off in theradial direction.